/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.pinot.core.operator;

import java.util.Map;
import org.apache.pinot.common.request.context.ExpressionContext;
import org.apache.pinot.core.operator.blocks.ValueBlock;


public abstract class BaseProjectOperator<T extends ValueBlock> extends BaseOperator<T> {

  /**
   * Returns a map from source column name to context.
   */
  public abstract Map<String, ColumnContext> getSourceColumnContextMap();

  /**
   * Returns the result column context. Without transform, the source and result column context are the same.
   */
  public abstract ColumnContext getResultColumnContext(ExpressionContext expression);

  /**
   * Returns the number of columns projected.
   */
  public int getNumColumnsProjected() {
    return getSourceColumnContextMap().size();
  }
}
